ttf_parser/tables/cmap/
format13.rs

1// https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-13-many-to-one-range-mappings
2
3use core::convert::TryFrom;
4
5use super::format12::SequentialMapGroup;
6use crate::parser::{LazyArray32, Stream};
7use crate::GlyphId;
8
9/// A [format 13](https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-13-segmented-coverage)
10/// subtable.
11#[derive(Clone, Copy)]
12pub struct Subtable13<'a> {
13    groups: LazyArray32<'a, SequentialMapGroup>,
14}
15
16impl<'a> Subtable13<'a> {
17    /// Parses a subtable from raw data.
18    pub fn parse(data: &'a [u8]) -> Option<Self> {
19        let mut s = Stream::new(data);
20        s.skip::<u16>(); // format
21        s.skip::<u16>(); // reserved
22        s.skip::<u32>(); // length
23        s.skip::<u32>(); // language
24        let count = s.read::<u32>()?;
25        let groups = s.read_array32::<super::format12::SequentialMapGroup>(count)?;
26        Some(Self { groups })
27    }
28
29    /// Returns a glyph index for a code point.
30    pub fn glyph_index(&self, code_point: u32) -> Option<GlyphId> {
31        for group in self.groups {
32            let start_char_code = group.start_char_code;
33            if code_point >= start_char_code && code_point <= group.end_char_code {
34                return u16::try_from(group.start_glyph_id).ok().map(GlyphId);
35            }
36        }
37
38        None
39    }
40
41    /// Calls `f` for each codepoint defined in this table.
42    pub fn codepoints(&self, mut f: impl FnMut(u32)) {
43        for group in self.groups {
44            for code_point in group.start_char_code..=group.end_char_code {
45                f(code_point);
46            }
47        }
48    }
49}
50
51impl core::fmt::Debug for Subtable13<'_> {
52    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
53        write!(f, "Subtable13 {{ ... }}")
54    }
55}
ttf_parser/tables/cmap/format13.rs

ttf_parser/tables/cmap/
format13.rs
